What does POP3, which runs on port 110, primarily do?

POP3, or Post Office Protocol version 3, is mainly utilized for receiving emails from a mail server. When a user accesses their email through a client configuration that utilizes POP3, the emails are downloaded from the server to the user's local device. This allows the user to view and interact with their emails offline, as the email client typically stores copies of the emails locally after downloading them.

The key aspect of POP3 is its operation on port 110, which is designated specifically for this protocol, emphasizing its primary role in the email retrieval process. POP3 is designed to allow users to fetch their emails rather than manage or send mail, which distinguishes it from other protocols like SMTP (Simple Mail Transfer Protocol), which is responsible for sending emails. In summary, POP3's core functionality revolves around receiving emails from an email server, making it integral to the email communication process for users who prefer to manage their emails locally.